Highly Efficient Cell Membrane Tracker Based on a Solvatochromic Dye with Near-Infrared Emission

The cell membrane is composed of a phospholipid bilayer with embedded proteins and maintains cell homeostasis through dynamic changes. An abnormal cell membrane shape could be a sign of unhealthy cells. Probes for subcellular fluorescence imaging that can identify the abnormal plasma membrane and record the dynamic changes are needed. Based on a solvatochromic dye with a near-infrared emission strategy, the amphipathic molecule (E)-2,2′-((4-(2-(4-(dicyanomethylene)-4H-chromen-2-yl)­vinyl)­phenyl)­azanediyl)­bis­(ethane-1-sulfonic acid) (MRL) contained a hydrophilic sulfo group and a hydrophobic chromone group, which was designed and synthesized for staining the cell membrane and monitoring the morphology of the membranes under different conditions. MRL exhibited an excellent photostability and low cytotoxicity; when cells were incubated with MRL, cell membranes were specifically labeled. MRL is capable of long-term monitoring of the morphological changes of cell membrane.